January is a month most gardeners would rather skip. The excitement and festivities associated with the holiday season are over, and ahead lies the prospect of eight bleak, dreary weeks of winter. All is not lost, however, since it is at this time of the year that interior plants brighten our days and allow us to enjoy plants when our psyche needs it most. Few other genera of plants offer “indoor gardeners” a wider array of choices than does Philodendron. Let’s take a closer look at this popular group of plants.
Philodendron is a large genus in the Araceae family that contains some the most attractive tropical plants known. Its name is derived from the Greek words philo (love), and dendron (tree). Literally interpreted, its name means “lover of trees” and refers to the fact that many members of this genus are vines that (in nature) use trees as a means of support. Additional to the climbers, the genus also contains self-heading (non-vining) species.
Given the fact many philodendrons can be found in nature under the canopies of heavily foliated trees, they are capable of growing at relatively low light intensities. This attribute makes them good candidates for use as interior (house) plants since most indoor settings lack appreciable levels of light even though they might appear bright to the human eye.
An excellent example of a low-light philodendron is heartleaf philodendron (P. scandens oxycardium) which probably is the most popular interior plant in America today. An excellent choice for beginners, it has the ability to tolerate as little as 15 foot candles of light. However, it requires at least 200 to really thrive and develop its true, mature form. It is ideal for dish gardens or trained on a support (totem) in larger containers. A look-alike often confused with heartleaf philodendron is pothos (Epipremnum aureum). It, too, is an excellent low-light, vining plant but normally has foliage variegated with yellow or creamy white.
Spade-leaf philodendron (P. domesticum) is another easy-to-grow, popular member of the genus. It has glossy, arrow-shaped leaves that often achieve a length of 12 inches when grown as an interior plant. It appreciates a bit more light than heartleaf philodendron and should be located in a moderate to bright interior location. Since it is somewhat weak-stemmed, it normally is grown attached to a totem.
One of the more popular self-heading philodendrons is lacy tree philodendron (P. selloum). It has large, imposing leaves with finger-like projections and requires a lot of space. Lacy tree philodendron is a full-sun plant in nature but can adapt to lower levels indoors. Given medium to bright amounts of light and time to grow, it is spectacular when used as a specimen plant.
Recently, a number of hybrid philodendrons have been introduced to the gardening world. Most are considered self-heading and are prized for their colorful new foliage which, in most cases, matures to a shade of green. Their mature size depends upon parentage, but most do well in larger containers (eight inches or more) with a totem for support. Generally, hybrids require medium to bright indirect light to retain their foliage color and to thrive.
Popular hybrid philodendron cultivars along with distinguishing characteristics include:
Philodendrons grow well in a porous, soilless potting medium that retains goodly amounts of moisture. When fertilizer is needed, ordinary “house plant” fertilizer used according to label directions will suffice. Philodendrons have relatively few pests and are quite fond of warm interior temperatures typical of most homes. Watering frequency depends on size of container, plant size and interior setting. Keeping the growing medium “uniformly moist” is a good rule to follow.
Like other plants native to the tropics, philodendrons thrive under conditions of high relative humidity. This presents a problem as we move plants indoors. Astoundingly, the average interior setting during winter has a relative humidity lower than that of the Sahara desert. Therefore, the use of a home humidifier should be encouraged since it will improve the environment for plants (and people) who reside there.
In closing, it must be noted that all philodendrons are considered to be toxic since they contain varying concentrations of needle-shaped calcium oxalate crystals known as raphides. In nature, these crystals serve as a defense mechanism against herbivores. Calcium oxalate crystals have an irritant action on skin and (especially) on soft tissue internal tissue. Accidental ingestion results in a severe burning sensation in the mouth and throat and warrants immediate medical attention. Therefore, care should be taken to keep philodendrons out of the reach of children and pets.
REVISED: January 3, 2013